The HPC provides an intellectual focal point around which to construct multidisciplinary networks of investigators. A common denominator to this diverse research activity is the laboratory-based diagnostic methods which are central to STD research and their integration with population sciences. We therefore propose the establishment of an STD Diagnostic Core within the HPC to facilitate cross-disciplinary collaboration and to support studies of STD-related problems. The STD Core will be built around a Reference Laboratory for Diagnostic Testing, which will provide expertise and service for fee, and will promote information exchange and collaboration through seminars and informal contacts. We anticipate that the STD Diagnostic Core will provide an intellectual focus for STD and HIV research, and will attract new investigators as HPC associates.